Study On Cementing Strength Of Surface Treatment Of Casing By Roughening

With the rapid development of the national economy, the consumer demand for energy in the country has increased year by year. Oil as an important energy base of national economic development, improve the exploration and development technology of petroleum in our country has great effects on the economy. In recent year, many domestic oilfield development has just come into medium term and later stage, water cut of the wells increases rapidly, main oil rock development move into high water cut period, development objects point to the oil sheet. However, the permeability of oil sheet is low, there are great differences in the interlayer pore pressure, and the interlayer is very thin.Then the development process needs a series of stimulation measures such as perforation, acidize, fracturing and high pressure water injection. The down hole geological conditions of oil sheet is very complicate, which will has heavily negative effect to a series of stimulation measures of oil and gas exploitation, if development cementing quality is bad.The advantages and disadvantages of cement quality are affected with many factors, which of the condition of casing surface is one of the important factors. At present, based on the first interface of cementing, it research on slurry property more and the smooth degree of casing surface less. In order to overcome the smooth casing surface and the bad consolidation between cement and casing, especially for the different expansion coefficient of the casing in the thermal recovery well,cement and bottom layer, so it causes movement between casing and cement sheath to lead casing damage when gas injection. Therefore it’s necessary to research a kind of new roughening casing on the outer surface whose application scope is more widely. The casing can improve effectively cementing strength between casing and cement sheath, and it can reduce damaged condition of casing. It’s helpful to improve cementing quality of development well in the old oil region of national major oil field, extend the exploitation life of development well and ensure long-term development and stable production in the major oil field. From the improvement of cementing quality and application requirements including channeling prevention, channeling blocking and preventing damage of casing program, this paper studies the effect and application problems of cementing strength based on the first interface of cementing for treatment method of different roughening on the outer surface of cementing casing, and it establishes the corresponding optimization theory and project. Through mechanic analysis of cementing strength based on the first interface of cementing, the mechanics model is established, which can reflect cementing strength between the casing of different roughening surface in various complicated cases and cement sheath. According to the mechanics model, the calculation method which calculates the corresponding cementing strength is designed. The experiments included the hydraulic cementing strength, shearing cementing strength and bond strength are experimented in the different projects. In the different projects each of cementing strength is measured, compared with calculation results, the influence between casing of different roughening and cementing strength of cement is analyzed. In various complicated cases, a kind of optimum plan about roughening of casing surface is found. Finally, the research for the influence between roughening treatment on the casing surface and cementing strength is applied in cement quality of optimization in oil field and late production.